A thread wound golf ball is a golf ball composed of a center (liquid center or solid center), a thread rubber layer formed by winding a thread rubber in a stretched state around the center, and a cover which covers the thread rubber layer.
It is necessary for a golf ball to have a suitable resilience performance in order that the golf ball may have excellent flying performances. In the case of the thread wound golf ball, the thread rubber layer has a great effect on resilience performances and, therefore, the characteristics of the thread rubber are considered to be particularly important.
The thread rubber is normally prepared by molding a mixture containing a natural rubber or an isoprene rubber or a rubber blend thereof as a base rubber, vulcanizing agents, vulcanizing accelerators, vulcanizing accelerator auxiliaries, antioxidants and, if necessary, fillers, softening agents, etc. into a thin sheet-like product and cutting the resulting sheet-like product after vulcanization, or solidifying a latex to give a sheet and cutting the sheet after vulcanization.
Furthermore, inorganic powders having excellent lubricity (e.g. talc, etc.) are adhered to the surface of the rubber sheet before vulcanization in order to prevent adhesion between sheets when sheets are peeled off after vulcanization, or to obtain a thread wound golf ball having the large resilience coefficient by controlling a friction force between the thread rubber and the tension controlling pulley so as to stretch the thread rubber in a predetermined amount when the thread wound core is prepared by winding the thread rubber around the center.
However, there is the problem that talc adhered to the surface of the thread rubber flies about, from the surface of the thread rubber into the environment, when the thread wound core is prepared by winding the thread rubber with stretching around its center, thereby making the working atmosphere worse.
However, when the flying of talc during working is prevented by decreasing the amount of talc to be adhered on the surface of the thread rubber, the peeling between sheets becomes difficult or the thread rubber adheres to the tension control pulley when the thread wound core is prepared by winding the thread rubber around the center, which results in cutting of the thread rubber.